Objects disappear after moving

I have a page in Lectora where I have a number of buttons with corresponding text. After the user clicks each button the corresponding text appears. I have variables set up to monitor when all buttons have been clicked. After all have been clicked, the buttons and text move up on the page to make room for an image that appears at the bottom. It works great when I click each button and wait a second before I click the next butoon. If I click thru the buttons without pausing at all, after the items move up on the page, they disappear. Has anyone ever encountered this problem and if so, how did you fix it?